<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>websocket</title>
</head>
<script>
    var socket;
    // 先判断当前浏览器是否支持websocket编程
    if (window.WebSocket) {
        // go on
        socket = new WebSocket("ws://localhost:7000/hello");
        // 相当于channelReado,ev 收到服务器端回送的消息
        console.log(socket.readyState)
        console.log(WebSocket.OPEN)
        socket.onmessage = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n" + ev.data;
        }
        socket.onopen = function (ev) {
            // 此函数相当于连接开启
            var rt = document.getElementById("responseText");
            rt.value = "连接开启了...";
        }
        socket.onclose = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value+ "\n" + "连接关闭了...";
        }
    } else {
        alert("当前浏览器不支持websocket")
    }

    // 发送消息到服务器
    function send(message) {
        if (!window.socket) {
            // 先判断socket是否创建好
            return;
        }
        if (socket.readyState === WebSocket.OPEN) {
            // 通过socket 发送消息
            console.log(message)
            socket.send(message);
        } else {
            alert("连接没有开启...")
        }
    }

</script>
<body>
    <form onsubmit="return false">
        <textarea name="message" style="height: 300px; width: 300px">
        </textarea>
        <input type="button" value="发送消息" onclick="send(this.form.message.value)">
        <textarea id="responseText" style="height: 300px; width: 300px"></textarea>
        <input type="button" value="清空内容" onclick="document.getElementById('responseText').value=''">
    </form>
</body>
</html>